Early Miocene (3)
Discoaster (12)
Sphenolithus (20)
Helicosphaera (14)
Description: Large to very large rosette-shaped discoasters with 16-35 rays joined along most of their length with simple ray tips.
Remarks:
Range: NP9 to NP11.
Neogene: Discoaster
Paleogene: Discoaster multiradiatus